Partial knee replacement surgery, also called unicompartmental knee arthroplasty, is routinely considered for the treatment of osteoarthritis of the knee joint. Partial knee replacement surgery has generated significant interest because it entails a smaller incision and faster recovery than traditional total joint replacement surgery.
When partial knee replacement is performed, the bone and cartilage on the end of the femur and top of the tibia are removed. This is performed using precise instruments to create exact surfaces to accommodate the implant. A knee replacement implant made of various biocompatible materials such as metal or plastic is then, placed to function as a new knee joint. Depending on the condition of the cartilage on the undersurface of the kneecap, this may also be replaced. The knee replacement implant typically comprises (i) a femoral component, made of metal and which fits on the femur, (ii) a tibial component, made of metal and which fits on the tibia, (iii) a patellar component, made of plastic and which replaces the cartilage on the undersurface of the kneecap, and (iv) a plastic insert which fits between the femoral and tibial components.